Power-transmission belt



E. L. BURRELL.

POWER TRANSMISSION BELT.

APPLICATION FILED MAY 9. 1917.

. Patented Nov. 15, 1921.

nanns'r L. scanner. or CHICAGO, tumors.

rowmc-trnnnsmrssron BELT.

Specification of Letters latent.

Application filed Kay 9, 1917. Serial No. 167,411.

I '0 all whom it may concern:

Be it known that I, ERNEST L. B RRELL, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Power-Transmission Belts, of which the following is a specification.

The main object of this invention is to provide an improved form of power transmission belt built up of superimposed layers of fabric, so as to be fully as durable as leather beltin and in all respects a practical substitute therefor, et materially less expensive.

The several views shown in the accompanying drawings illustrate the manner in which the improved belt is manufactured and some of the conditions incident to its use.

Figure 1 is a perspective 'view of a section of the thick cotton belting material which forms the body of the belt.

Fig. 2 is a section of the thin, closely woven sheet material out of which the remainder of the belt is built up.

Fig. 3 is a section of the completed belt.

Fig. 4 is a diagrammatic view illustrating the manner in which the belt wraps around a pulley.

Fig. 5 is a diagrammatic view illustrating the relative stretching and compressing stresses within the belt as it passes over a pulley.

Fig. 6 is a perspective view of the belt as applied for use with tight and loose pulleys, so as to be shifted from one to the other.

The materials which enter into the manufacture of this belting are two kinds of fabric and a glue composition. One fabric 7 is a thick, coarsely woven material commonly known in the trade as cotton-woven beltin such as is extensively used in the manuf cture of various kinds of belting. The other fabric 8 is a comparatively thin and rather finely woven material, such as mi ht be designated a light-weight canvas. be kind preferably used is-commonly known in the trade as army duck.

Various kinds of cement can of course be used with perhaps varying results. That which has been found most satisfactory is a composition of paper pulp and hide or bone glue, such as has een described in my Patent No. 1,116,237, granted November 3, 1914.

The improved belting is manufactured in substantially the following manner:

First, a strip of the coarse fabric 7 is thor oughly coated on one face with a quantity of the composition glue, upon which is laced the first layer of thin fabric 8, which is also coated with the glue. These two layers are then put under pressure and allowed to stand Patented Nov. 15,1921.

until thoroughly dry. Next, a second layer of thin fabric 8, thoroughly coated with the glue composition, is applied'in a similar manner upon the first layer of fabric 8, and allowed to dry under pressure. This is repeated until the combined thickness of the layers of thin fabric 8 is substantially the.

same as the thickness of the coarse fabric 7.

This process of building u the belt and allowing each layer of the fiibric 8 to thoroughly dry under pressure before another layer is applied, causes the layers of the fabr10 8, on account of their comparative thinness, to become thoroughly saturated or impregnated with the glue composition, so that said thin layers are formed into practically a homogeneous mass. In a way, these thin layers of fabric might be said to com rise one ply, and the layer of coarse fabric another ply of the belt. Although the glue composition does not im regnate the pores and meshes ofthe fabric 7 to the extent that it does the thin layers, yet said glue composition is caused to penetrate considerably into the pores and meshes of the adjacent face of the fabric 7, so that the two plies or sections of the belt are firmly united.

It is quite important that in building up this beltin the combined thickness of the layers of abric 8 be substantially equal to the thickness of the fabric 7, so that the juncture of the two plies or sections ofthe belt is substantially halfway between the outer surfaces thereof. Thus, when the belt is traveling around. a pulley, as shown in Fig. 4, the juncture is in a neutral position between the compressional stresses of the innermost section and the tensional stresses of the outer section. The relative extent of these stresses is diagrammatically represented in Fig. 5,

thus neutralized at the middle plane of the belt, there is no stretching and compressing of the belt along said line of juncture, and tlius little, if any, tendency to separate the p The belting is usually used with the layer of fabric 7 facing inwardly, as it is the more susceptible to compression without materially affecting its texture, whereas the layers of fabric 8, being so; thoroughly impregnated with the glue composition, are quite firmly secured together and are more susceptible to the tensional strains.

Another verypractical and beneficial advantage which is a feature of 'this belting is that excessive wearing along the lateral edges thereof does not produce fraying as is usually incident to other kinds of fabric belting. This is due to the. fact that the edges of layers of fabric 8 present a mass of thread ends embedded in the glue composition. It is therefore possible to make use of this belt in connection with power transmission, where it is necessary to use a belt shifter formoving the belt from one pulley to another, as has been'illustrated in Fig. 6.

Although but one method of preparin this belting has been shown and describe itwill be understood that the character of the material and method of building it up may be varied or modified without departing from the spirit of the inventon as defined bythe following claims.

I claim:

1. A power transmission belt, comprising two superimposed plies of fabric firmly sec-ured'together by cement, one ply consisting of coarse woven strands, and the other consisting offine woven strands, said plies being of substantially equal thickness so as to locate the uncturebetween them in a neutral position between the compressional and tension'al strains to which said belt is subjected' when in use.

2. A power transmission belt, comprising two superimposed plies of fabric firmly secured together by cement, one ply consisting of a single thick sheet of coarse. woven strands, and the other consisting of a multiplicity of thin sheets of fine woven strands,

said plles being of substantially equal thickness so as tolocate the juncture between them in a neutral position between the compressional and tensional strains to which said belt is subjected when in use.

3. As an article of manufacture, a power transmission belt, com rising a comparatively thick layer of fa ric, and a lurality of comparatively thin layers of fabric superimposed upon one face of said thick layer of fabric, said thin layers of fabric being secured together and upon said thick layer by cement which has been caused to fill the pores and meshes of said thin fabric, so as to combine the strands of said fabric and the cement to constitute substantially a homogeneous mass.

4. As an article of manufacture, a power transmission belt, comprising a com uratively thick layer of fabric, and a p urality of comparatively thin layers of fabric superimposed upon one face of said thick layer of fabric,said thin layers of fabric belng secured together and u on said thick layer by cement which has een caused to till the pores and meshes of said thick fabric so as to combine the strands ofsaid thin fabric and cement to constitute a substantially homogeneous mass, the combined thickness of said superimposed cement-impregnated thin layers-being substantially the as the thicknessof said one thick layer of fabric, so as to locate the juncture between said thick layer and said plurality of thin layers in a neutral position between the compressional and tensional strains to which said belt is subjected when in use.

5. As an article of manufacture, a power transmission belt, comprising a layer of comparatively thick, coarse, woven cotton belting material, and a plurality of layers of-comparatively thin, fine woven material superimposed on one face of said thick layer, said thin layers of fabric being secured together and upon said thick layer by cement which has been caused to fill the pores and meshes of said thin layers, so as to combine the strands of said thin fabric and cement toconstitute substantially a homogeneous mass, said cement being also caused to penetrate into the pores and meshes of the adjacent face of said-thick layer, the combined thickness of said superimposed cement-impregnated thin layers being substantially the same as the thickness of said thick layer.

Sgned at Chicago this 7th day of May. 191

ERNEST L. BURRELL. 

